Elevator car flexible guide clamp safety



Aug. 30, 1955 c. R. CALLAWAY 2,716,467

ELEVATOR CAR FLEXIBLE GUIDE CLAMP SAFETY Filed Oct. 7, 1952 4Sheets-Sheet 1 0 0 0 0 0 o 74 0 l) o 0 3a 40 40 o V INVENTOR.(Z4PEA/CEE64AMMV A r TOP/W5) Aug. 30, 1955 c. R. CALLAWAY ELEVATOR CARFLEXIBLE GUIDE CLAMP SAFETY 4 Sheets-Sheet 2 Filed Oct. 7, 1952 w NE 3 Afiih 3 wk MN 0% vm 1 vm \0 m H m wk 3 mm NW .A A MR Q T A v W QM.N\\ 1 wP m Q P O m N\\ E I vm mm NW v, M 5 Mn N N L e m m w C T IDA. g P. P m 6w r NQ E rum PFC wm 1f m Aug. 30, 1955 c. R. CALLAWAY 2,716,467

ELEVATOR CAR FLEXIBLE GUIDE} CLAMP SAFETY Filed Oct. 7, 1952 4Sheets-Sheet 5 74 o 0 74 o o a a 0 o o F5 5 INVENTOR.

F) TTOP/VE) Aug. 30, 1955 c. R. CALLAWAY 2,716,467

ELEVATOR CAR FLEXIBLE GUIDE CLAMP SAFETY Filed Oct. 7, 1952 4Sheets-Sheet 4 United States Patent ELEVATOR CAR FLEXIBLE GUIDE CLAMPSAFETY Application October 7, 1952, Serial No. 313,551

14 Claims. (Cl. 18790) My invention relates to an improved elevator carflexible guide clamp safety and more particularly to a safety device forelevator cars in which the elevator car is brought 8 to an emergencystop by applying a braking action upon the guide rails in the event theelevator exceeds a predetermined speed of downward movement for anycause.

Safety devices for stopping the elevator car in the event of excessivedownward speed are known to the art. These devices usually take the formof a spring-actuatedbrake adapted to clamp the guide rails. If theclamping pressure exercised by the spring is too weak, the car willnotbe brought to a stop. If the clamping pressure is too great, the car maystop too suddenly, with attendant damage to apparatus or injury to thepassengers of the car.

One object of my invention is to provide a flexible guide clamp safetydevice for elevator cars in which heavy spring pressure may be employedand yet insure that the car is brought to a stop in such gradual manneras not to injure apparatus or passengers.

Another object of my invention is to provide a flexible guide clampsafety in which a constant retarding force will be applied even thoughthe elevator is traveling at high speeds.

Another object of my invention is to provide a flexible guide clampsafety which insures the alignment of the clamping jaws with the guiderails at all times.

A further object of my invention is to provide a flexible guide clampsafety which will not suddenly jam or grip the guide rails to bring thecar to a sudden halt with the attendant danger.

Another object of my invention is to provide a flexible guide clampsafety having clamping jaws which will align themselves correctly withthe guide rails at all times independent of imperfections in the guiderails.

Other and further objects of my invention will appear from the followingdescription.

In general, my invention contemplates the provision of a pair of jawlevers biased to a fixedposition by a stout spring. Adjacent the guiderails I position a pair of wedge-shaped clamping jaws adapted to bemoved into engagement with the guide rails when it is desired to brakethe elevator car. Between each pair comprising one of the jaw levers andone of the wedge-shaped jaws I provide a plurality of balls disposed ina ball carrier. I provide means to position the ball carrier correctlywith respect K) the jaws in all positions. The wedging action betweenthe guide rails and the jaw levers is resisted by the stout spring, thethrust being transmitted through the balls. The arrangement is such thatwhen the clamping jaws have reached their limit of motion, a constantretarding force will be exerted upon the guide rails by the springswhich bias the jaws. The balls insure that the wedge-shaped clampingjaws will always align them- .selves properly with the surfaces of theguide rails, the

thrust being transmitted through spherical surfaces.

,be attached to the car at the top.

I provide a convenient hydraulic means for releasing the clamping actionas it has taken place.

In the accompanying drawings which form part of the instantspecification and which are tobe read in conjunction therewith and inwhich like reference numerals are used to indicate like parts in thevarious views:

Figure. 1 is a diagrammatic view showing an elevator installationequipped with a guide clamp safety.

Figure 2 is a side elevation of the bottom of an elevator car equippedwith a flexible guide clamp safety of my invention.

Figure 3 is a bottom plan view of the flexible guide clamp safety shownin Figure 2.

Figure 4 is a sectional view drawn on an enlarged scale viewed along theline 44 of Figure 2.

Figure 5 is a sectional view drawn right side up, on an enlarged scale,taken along the line 5-5 of Figure 3.

Figure 6 is a sectional view drawn on an enlarged scale and viewed rightside up taken along the line 66 of Figure 3.

Figure 7 is a sectional view drawn on an enlarged scale viewed along theline 77 of Figure 2.

Figure 8 is a diagrammatic view showing the mode of hydraulicallyreleasing the spring pressure which actuates the clamping jaws.

Figure 9 is a sectional view drawn on an enlarged scale viewed along theline 8-8 of Figure 4.

Referring now to Figure 1, the elevator car 10 is adapted to be raisedand lowered by a hoisting cable 12 through the medium of a hoistingmotor 14, the other end of the cable 16 being provided with a customarycounterweight 18. The safety assembly is indicated generally by thereference numeral 20 and is secured to the bottom of the elevator car10. It is to be understood, of course, that the guide clamp safety may,if desired,

An endless flexible member, such as a Wire rope 22, is positioned upon apair of sheaves 24 and 26 and extends through the elevator shaft fromtop to bottom throughout the amplitude of travel of the elevator. Afriction clamp 28 is secured to the safety rope 22. The clamp 28 isattached to the elevator car by a springpositioned arm 30. A tail rope32 extends from the friction clamp 28 to the guide clamp safetyassembly. A governor 34 is adapted to be driven by the rotation of thesheave 26. As the elevator moves upwardly and downwardly, the safetyrope is moved along with the elevator car through the friction clamp 28and the connecting arm 30. When the elevator exceeds the downward velocity to which the governor 34 is set, the governor will stop the movementof the sheave 26, thus immobilizing the safety rope 22. The downwardmotion of the car relative tothe stationary friction clamp 28 will causea tug or pull to be exerted on the tail rope 32. The tug or pull of thetail rope sets the guide clamp safety, as will be described more fullyhereinafter.

Referring now to Figure 2, the elevator car 10 is mounted upon asuitable stout framework 36 which may comprise a pair of I-beams 38 towhich frame members 40 are secured in any appropriate manner, therebeing one frame 40 at each side of the elevator car adjacent each guiderail 42. I pivot a pair of levers 44 and 46 intermediate their ends toeach frame 40 by means of hinge pins 48 and 50. The outer end 52 of thelever '44 and the outer end 54 of the lever 46 are disposed on theopposite sides of the flange 56 of the guide rail 42. The other end 58of lever 44 and the other end 60 of lever 46 are provided with openingsthrough which a bolt 62 passes. The ends of the bolt are threaded toreceive nuts 64 and 66. A spring 68 is positioned between the lever ends58 and 60 and serves to bias these lever ends outwardly. A bearing disk70 is positioned between one end of spring 68 and the lever end 58. Asimilar bearing disk 72 is positioned between the other end of thespring 68 and the lever end 60. The position of the nuts 64 and 66determines the initial position of the lever jaws 52 and S4.

Rotatably mounted in suitable bearings carried by the frames 40 Iposition a pair of shafts 74 and 76, these shafts running the fulllength of the assembly. A crank 78 is keyed to each end of a shaft 74for rotation therewith and a similar crank 80 is keyed to each end ofcrank 76 for rotation therewith, as can be seen by reference to Figure4. Each lever jaw 52 and 54 is formed with an inclined surface 82 whichdiverges fromthe guide rail flange 56 in a downward direction. Aclamping jaw 34 is carried by the end of crank 78 through a link 86. Aball carrier 88 is positioned between the clamping jaw 84 and the jawlever surface 82. A plurality of thrust transmitting balls 90 arecarried by the ball carrier 88. The ball carrier is connected to thecrank 78 through a link 92.

The construction on the other side of the guide rail 56 is symmetricalto that just described. A clamping jaw 94 positioned on the other sideof the flange 56 of the guide rail corresponds to the clamping jaw 84.The link 96 corresponds to link 86 and connects the clamping jaw 94 tothe end of crank 80. The ball carrier 98 corresponds to the ball carrier88 and the balls 100 correspond to the balls 90. The link 102 connectsthe ball carrier to the crank 80 intermediate its ends.

It will be observed, by reference to Figure 4, that the ball carrier 88is displaced downwardly from the upper edge of the inclined surface 82through a convenient distance. The clamping jaw 84 is displaceddownwardly from the upper edge of the ball carrier 88 through this samedistance. To move the parts to their clamping position, that is, withthe clamping jaw 84 horizontally in alignment with the lever jaw 52 theball carrier will have to move through a certain distance while theclamping jaw 84 will have to move through twice this distance. Tomaintain the parts in their proper relationship to preclude slidingdisplacement of the ball carrier I position the links 92 and 86 suchthat the ball carrier will move at one-half the speed of the clampingjaw in an upward direction. This insures the parts will be maintained intheir correct position so that the thrust will be transmitted throughall of the balls 90 at the maximum thrust.

Referring now to Figure 9, the end of each lever jaw is provided with aplate 104 secured thereto by a plurality of bolts 106 to preventdisplacement of the clamping jaws 84 and 94 and the ball carriers 88 and98 longitudinally of the assembly. The surface 108 of the clamping jaw84 which contacts the guide rail flange 56 is provided with a pluralityof grooves 110 into which grease and dirt which might be present on theguide rail flange surface can be scraped when contact between theclamping jaws and the guide rail flange is made.

A sprocket wheel 112 is keyed to the shaft 74 for rotation therewith. Ikey a sprocket wheel 114 to the shaft 76 for rotation therewith. Thesesprocket wheels are connected by a crossed drive chain 116 to insurethat shafts 74 and 76 will always rotate in opposite directions. A crank118 is keyed to shaft 74 for rotation therewith. An angle iron 120 iscarried by the I beams 38 and secured thereto in any appropriate manner.The flange 122 of the angle iron 120 carries a rod 124 to the end ofwhich I swivelly mount a guide block 126. A socket block 128 ispivotally mounted to the end of crank 118. A rod 130 extends from thesocket block 128 through guide block 126. Around the rod I position aspring 132. The thrust of spring 132 will rotate the shaft 74 in acounterclockwise direction as viewed in Figure 7 and in a clockwisedirection as viewed in Figure 4. The drive chain 116, therefore,

will rotate the sprocket wheel 114 in a clockwise direction as viewed inFigure 7 and hence will rotate the shaft 76 in a clockwise direction asviewed in Figure 7. As viewed in Figure 4, however, the shaft 76 willappear to rotate in a counterclockwise direction. Accordingly, the crank78 will rotate in a clockwise direction as viewed in Figure 4 and thecrank will rotate in a counterclockwise direction as viewed in Figure 4.

The end of frame 40 is provided with a stop lug 134 to position thecranks in a convenient non-clamping position with sufficient clearancebetween the clamping jaw surfaces and the guide rail flange 56. Thespring 132 serves to maintain the parts in this position. Secured toshaft 76 for rotation therewith I provide a sheave 136 around which thetail rope 32 is wound. The end of the tail rope is secured to the sheaveby a clamp 138, as can be seen by reference to Figure 7. Whenever theelevator car moves downwardly at a velocity in excess of that to whichthe governor 34 is set, the governor will stop the safety rope 22. Thedownward motion of the car with respect to the stationary safety ropewill tug upon the tail rope 32. When the tail rope 32 is pulled it willrotate the sheave 136 in the direction of the arrow shown in Figure 7,that is, in a counterclockwise direction This will rotate the shaft 76in a counterclockwise direction and hence the sprocket wheel 114 in acounterclockwise direction, as viewed in Figure 7. This will rotate thesprocket wheel 112 in a clockwise direction as viewed in Figure 7through the crossed chain 116. These directions of rotation under theinfluence of the tug upon the tail rope 32 will be in the direction ofthe arrows in Figure 4. Shaft 74, in rotating in a counterclockwisedirection, will lift the clamping jaw 84 and the ball carrier 88 at halfthe speed of travel of the clamping jaw. Similarly, the clockwiserotation of the shaft 76 will, through the crank 80 and the connectinglinks 96 and 102, lift the clamping jaw 94 at a predetermined speed andwill lift the ball carrier 98 at half this speed. Due to the wedgeshapedconstruction of the clamping jaws they will be carnmed inwardly,gripping the clamp 56 of the guide rail. It is understood, of course,that the clamping jaws on both ends of the assembly will be carnrnedinwardly to grip the side rails at each end of the elevator car. Theclamping thrust will be transmitted through the balls and to therespective lever jaws 52 and 54 tending to thrust the lever jawsoutwardly. This outward motion 01' the lever jaws 52 and 54 will, as canreadily be seen by reference to Figure 3, force the lever ends 58 and 60inwardly against the action of the heavy spring 68. In this manner aconstant predetermined clamping pressure is applied to the guide railsproviding a constant retarding force which will smoothly and quicklybring the elevator car to a stop. The clamping jaws 84 and 94 areclamped by thrust transmitted through the balls 90 and 100. Anyirregularities in the guide rails will be readily accommodated for dueto the fact that the bearing surfaces between the jaws 84 and 94' arespherical by reason of the spherical shape of the balls. This permitsthe jaws to align themselves at all times. The connection of the jawsand the ball carriers to the cranks 78 and 80 insures the correctpositioning of the ball carriers with respect to the jaws in allpositions.

In order to prevent the fouling of the suspension cables of the elevatorby having the hoisting motor feed out .the cables after the car isstopped by my flexible guide clamp safety I position a switch 140 forcontrolling the motor 14 upon an appropriate support 142 carried by thebeams 38. An actuating crank 144 for the switch 140 is keyed to shaft 76for rotation therewith. Whenever the tail rope 32 rotates the shaft 76the actuating crank 144 will stop the motor.

After the elevator has been stopped it can only be freed by moving thecar upwardly. This usually involves shunning the switch 140 and hoistingthe eat to free the safety device. I I I In Figure 8 I have shown amodification of my 111-. vention which will enable the car to be freedwithout reversing its direction. The lever end 58 is formed with ahydraulic cylinder 73 having a piston 71 posttioned therein. The bolt 62is secured to the lever end 60 by the nuts 66, in a manner similar tothe construction shown in Figure 6. The lever end 58, however, isprovided with an opening 59 through which the bolt 62 passes. A stop nut61 is carried by the bolt normally to determine the outward position ofmovement of the lever end 58 under the influence of spring 68. The bolt62 extends outwardly through the cylinder end 75 and is secured to thepiston 71 by means of a nut 77. An appropriate reservoir 79 forhydraulic fluid is provided A hand pump 81 operable by a hand lever 83is adapted to pump fluid from the reservoir 79 past check valve 85through pipe 87 to the space 89 between the cylinder end 75 and the topof the piston 71. This will move the piston to the left, compressing thespring 68 between the ends 60 and 58 of the levers 46 and 44. Thismovement of the lever ends 60 and 58 toward each other under hydraulicpressure against the action of spring 68 will move the lever jaws 52 and54 away from each other, relieving the clamping action. As soon as theclamping thrust of the spring is relieved, the spring 132 will rotatethe shafts 74 and 76 to bring the cranks 78 and 80 to the position shownin Figure 4, thus freeing the safety device from its clamping position.small conduit 91 having an appropriately small crosssectional areaprovides for the leakage of fluid from the cylinder back to thereservoir 79. This fluid is forced through the bleeding conduit 91 bythe spring pressure 68 and gradually allows the spring pressure to movethe lever ends outwardly until they rest against the stop nuts 66 and61. This, again, places my safety device in a position to operate. Therestoration of the parts of the safety assembly to their nonoperatingposition automatically restores the elevator to operating conditionsince the switch 140 will be moved to a position completing the motorcircuit so that the elevator may again operate. I have found that anamplitude of motion of the piston 71 of two inches is ample to providefor releasing movement of the parts.

It will be seen that I have accomplished the objects of my invention. Ihave provided an elevator car flexible guide clamp safety which willfurnish a constant retarding force for an elevator car even though itmay be traveling at very high speeds when the safety operates. I haveprovided means for insuring the aligning of the clamping jaws with theguide rails irrespective of any local misalignment of the guide rails. Iprovide means for insuring correct positioning of the ball carrier withrespect to the stationary and movable jaws in all positions. My flexibleguide clamp safety is simple in construction and certain in operation.The clamping pressure may be readily adjusted in a convenient andexpeditious manner. The governor may be placed in any convenientlocation and, if desired, the friction clamp for the safety rope may beplaced at the bottom of the car instead of the top of the car, as iscustomary in the prior art. My construction is such that all danger ofseizing the rail by the clamping jaws and freezing them thereto iseliminated. In this manner injury to occupants of the car and damage tothe apparatus is avoided. If desired, means may readily be provided forfreeing the assembly after it is clamped without moving the carupwardly.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of myclaims. It is further obvious that various changes may be made indetails within the scope of my claims without departing from the 'spiritof my invention. therefore to be understood that my invention is not tobe limitedto 'the specific details shown and described.

'Having thus described my invention, what'I claim is: i 1. Inan'elevator car'flexible guide-clamp safety assembly a car, guide railsforthe car, a pair of levers carried by the car pivoted intermediatetheir ends, a spring positioned between the inner pair of lever endsurging them away from each other, means for limiting the movement of theinner lever ends under the influence of the spring, means forpositioning the outer lever ends'on'opposite sides of a guiderail andspaced therefrom, a pair of shafts, means for mounting the shafts on thecar for rotation, an arm secured to each shaft for rotation therewith,means forconnecting the shafts to rotate'in opposite directions, abearing element carrier positioned between one outer lever end and theguide rail, another bearing-element carrier positioned between the otherouter lever end and the guide rail, bearing elements carried by thecarriers, means for attaching respective carriers to respective arms-,aclamping block positioned between one carrier and the guide rail,another clamping block positioned between the other carrier and theguide rail, means for attaching the clamping blocks to respective arms,means responsive to a predetermined speed of descent of the elevator carfor rotating the shafts to lift the bearing element carriers and theclamping blocks whereby to clamp the guide rail between the clampingblocks, the construction being such that the clamping thrust will movethe outer ends of the levers away from each other against the action ofthe spring.

2. An elevator car flexible guide clamp safety assembly as in claim I,in which said outer lever ends are formed with surfaces which lie alongplanes diverging from each other in a downward direction, the bearingelements being adapted to engage said surfaces.

3. An elevator car flexible guide clamp safety assembly as in claim 1,in which said bearing elements comprise balls.

4. An elevator car flexible guide clamp safety assembly as in claim 1,in which said clamping blocks are wedge-shaped.

5. An elevator car flexible guide clamp safety assembly as in claim 1,in which said means for attaching the carriers -to the arms compriselinks pivotally secured to the arms and to the carriers.

6. An elevator car flexible guide clamp safety assembly as in claim 1,in which said means for attaching the clamping blocks to respective armscomprise links pivotally connected to respective clamping blocks andarms.

7. An elevator car flexible guide clamp safety assembly as in claim 1,in which each of the attaching means for the carriers is attached to itsarm between the arm shaft and the point of attachment to the arm of theclamping block.

8. An elevator car flexible guide clamp safety assembly as in claim 1,in which the distance of the point of attachment of each clamping blockto its arm from the center ofits shaft is twice the distance of thepoint of attachment of the carrier to the arm from the shaft center.

9. An elevator car flexible guide clamp safety assembly as in claim 1,including means for biasing the shafts to rotate the arms to move thebearing element carriers and the clamping blocks away from clampingposition.

10. An elevator car flexible guide clamp safety assembly as in claim 1,in which said means responsiveto a predetermined speed of descent of thecar for rotating the shafts includes a tail rope, a sheave secured toone of the shafts for rotation therewith, said tail rope beingpositioned about said sheave, a safety rope, means for controlling thespeed of the movement of the safety rope and means for attaching thetail rope to the safety rope.

11. An elevator car flexible guide clamp safety assem- It' is bly as inclaim 1, in which said elevator car is provided with a switch and meansresponsiveto the rotation of. one of said shafts for operating saidswitch. x 12. An elevator car flexible guide clamp safety 'assem bly asin claim 1, inwhich said means for limiting the movement of the innerlever ends under the influence of the spring includes a ,rod extendingaxially of the spring and passing through the lever ends and nutsthreadedly carried by the rods outboard of the lever ends.

13. An elevator car flexible guide-clamp safety assembly as in claim 1,in which said means for limiting the, movement of the inner lever endsunder the influence of the spring includes a rod extending axially ofthe spring and passing through the lever ends, nuts threadedly carriedby the rods outboard of the lever ends, a cylinder carried by one of thelever ends, a piston positioned in said cylinder, means for seeuringhoneend of the rod to the piston and means for introducing fluid underpres-. sure into the piston whereby to move the inner lever ends towardeach other against the action of the spring to release the guide clampsafety from clamped position.

carried by one of the lever ends, a piston positioned in said cylinder,means for securing one end of the rod to the piston, means forintroducing fluid under pressure into the piston whereby to move theinner lever ends toward each other against the action of the spring to 7release the guide clamp safety from clamped position and means forreleasing fluid pressure from the cylinder.

, References Cited in the file of this patent UNITED STATES PATENTS756,811 Baldwin Apr. 12, 1904 974,414 Mohnike Nov. 1, 1910 2,150,373Hymans Mar. 14, 1939

